Environmental Impacts of Biofuels

The growth of biofuel production from crops will have a direct impact on the land and the environment writes TheBioenergySite Senior Editor, Chris Harris.
calendar icon 28 November 2008
clock icon 5 minute read

One of the major reasons for producing biofuels is to reduce greenhouse gas emissions and to mitigate the effects of global warming produced by fossil fuels.

However, according to the Food and Agriculture Organisation of the UN, some unintended impacts of biofuel production are on land, water and biodiversity. They are affected by agricultural production and if the agricultural production is intensified then the side effects are even greater.

The common conception is that growing crops for biofuels will offset the greenhouse gas emissions because they directly remove carbon dioxide from the air.

However, the FAO in its The State of Food and Agriculture 2008 report, says that scientific studies have shown that different feedstocks grown for biofuels have different environmental effects.

"Depending on the methods used to produce the feedstock and process the fuel, some crops can even generate more greenhouse gases than do fossil fuels," the report says.

It warns that nitrous oxide that is released from fertilisers that might be put on the ground to help the crops grow will have 300 times more global warming effect than carbon dioxide.

It says that greenhouse gases can be emitted by both direct and indirect land use changes because of increased biofuels production by the conversion of land use from one crop to another.

There is also a difference in the greenhouse gas savings of different crops as maize produced for ethanol has an annual greenhouse gas saving of about 1.8 tonnes per hectare according to the report, but switchgrass, which is a second generation crop has a saving of 8.6 tonnes.

The FAO says that the amount of emissions produced throughout the production cycle also have to be taken into account and there is a balance to be drawn between the direct greenhouse gas savings, the emissions and the potentially valuable by-products produced in biofuel production.

The balance also has to be drawn between the greenhouse gas emissions produced in the production and burning of biofuels and the production and burning of fossil fuels.

These balances can vary between different feedstocks and different locations and production methods.

"Most studies have found that producing first-generation biofuels from current feedstocks results in emission reductions in the range of 20-60 per cent relative to fossil fuels, provided the most efficient systems are used and carbon releases deriving from land-use change are excluded," the report says.

However, it adds that Brazil has the best conversion rate and the highest savings with typical reductions of between 70 and 90 per cent.

One of the most telling impacts of biofuels is any change in land use that might take place.

The FAO says the impact is at the beginning of the production cycle and any change in land use might take years to balance out the effects and in some cases could show fossil fuels to be more efficient than the biofuels. This would be particularly relevant is rainforest, peatlands, savannahs or grasslands are used to grow feedstocks to produce ethanol or biodiesel.

Some studies have shown that in some cases more carbon would be sequestered by converting a cropland used for a biofuel feedstock to forest than the production of the fuel itself.

"If the objective of biofuel support policies is to mitigate global warming, then fuel efficiency and forest conservation and restoration would be more effective alternatives," the report says.

The FAO says that energy efficiency and conservation are just as important and can be more cost effective than production of biofuels.

"A comprehensive understanding of the relevant issues, including land-use change, and proper assessment of greenhouse gas balances are essential in order to ensure that bioenergy crops have a positive and sustainable impact on climate-protection efforts."

And the report adds: "In addition to the impacts of feedstock production on greenhouse gas emissions, biofuel processing and distribution can also have other environmental impacts."

The productivity of the land and crops, improved farming techniques and increases in yields also have an effect of the benefits of biofuel production. The FAO says that initially benefits in biofuel production might be obtained by increasing the land available for growing first generation crops, but eventually improved yields and growing second generation crops with different crop varieties and better agronomic practices are expected to become dominant.

The FAO warns that there can be a knock on effect in growing crops especially as feedstock for biofuels. It can displace other crops and create a greater demand for new land for growing new feedstocks. In Australia Canada and the US this has been seen as land that is used as non-cereal crop land at present, in the EU it is set aside land and in Latin America it is new uncultivated land.

This land grab to plant biofuel feedstock could see large swathes of land changing its use.

The sugar cane area of Brazil is expected to almost double to more than 10 million hectares over the next decade and along with the expansion of the Brazilian soybean area this could displace lands for livestock pasture and other crops. In the end this places pressure on uncultivated land.

Other significant pressures on the land are going to be seen in the intensification of crop production through new technology and impacts on the soil through water use and the potential scarcity of water. This could become a limiting factor in the production of biofuel crops and producing more biofuel crops will also have an effect on the water quality.

"Domestic government policy must become better informed of the international consequences of biofuel development. International dialogue, often through existing mechanisms, can help formulate realistic and achievable biofuel mandates and targets," the report concludes.

Further Reading

- You can view the full report by clicking here.

November 2008

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